This invention relates to detergent cleaning compositions which are particularly suitable for use in automatic dishwashers. In detail, the compositions herein comprise a binary active system and a particular enzyme, the compositions being substantially free of bleach components and brighteners. The binary active system comprises a nonionic surfactant, preferably an ethoxylated nonionic, and a compatibilizing agent which is represented by a sulfonated aromatic hydrotrope. The enzymes adapted for use herein have an iso-electric point greater than about 8.5. The constituents of the binary active system are present in major amounts, preferably in about equiponderal quantities. The compositions of this invention are capable of providing, during conventional use, markedly enhanced overall cleaning performance for a broad range of soils, and anti-redeposition benefits, particularly for soils composed of grease and grease-protein complexes. The instant compositions, in addition to the essential components, preferably comprise conventional dishwashing composition additives in the art-established levels for their known functions. Examples of such additives include sodium silicate solids, sodium carbonate, sodium bicarbonate, sodium sulfate and sodium phosphate. It is noteworthy that the compositions herein are capable of providing outstanding dishwashing performance in the total absence of phosphorus-containing detergent builders, or in the presence of a reduced level thereof as well as in fully polyphospnate built compositions.
Particularly preferred enzymes are proteolytic enzymes which exhibit a proteolytic activity of 80 to 100% of maximum activity when measured at pH 12 using the Anson hemoglobin method carried out in the presence of urea. When these particular enzymes are included the detergent compositions may be formulated without the sulfonated aromatic compatibilizing agent, while still retaining enhanced anti-redeposition properties.
Conventional automatic dishwashing compositions usually contain a low-foaming surface-active agent, a chlorine bleach, alkaline builder materials, and usual minor ingredients and additives. The incorporation of chlorine bleaches requires special processing and storage precautions to protect components which are subject to deterioration upon direct contact with active chlorine. The stability of the chlorine bleach is also critical and raises additional processing and storage difficulties. It is also known that detergent compositions for use in automatic dishwashers can tarnish silverware and damage metal trim on china as a result of the presence of chlorine-containing bleaches therein. Accordingly, there is a standing desire to formulate detergent compositions for use in automatic dishwashing operations which are free of active chlorine and which are capable of providing overall hard surface cleaning and appearance benefits comparable to or better than active chlorine-containing detergent compositions. This reformulation is particularly difficult in light of the fact that during automatic dishwashing operations, active chlorine prevents the formation and/or deposition of troublesome proteins and proteingrease complexes on the hard surfaces and no surfactant system is currently known capable of performing that function.
The disclosures of all Patents mentioned hereinafter are incorporated by reference.
The disclosures of U.S. pat. No. 3,549,539 to Mallows relate to machine dishwashing powders containing a nonylphenol-5-EO or a condensation product of a random C.sub.11 to C.sub.15 secondary alcohol and ethylene oxide with an HLB (hydrophilic-lipophilic balance) value between 11.5 and 13.5 and a polyethylene oxidepolypropylene oxide condensate that consists of between 5 and 25% polyethylene oxide and 95 to 75% polypropylene oxide and has a molecular weight between 1500 and 2700. It is disclosed that in addition to the above surfactant combination the machine dishwashing powder will normally contain from 5 to 30% of a silicate such as sodium metasilicate, from 5 to 30% of an oxidizing agent, from 25 to 70% of a calcium ion sequestrant and from 1 to 20% of an inorganic filler salt, such as sodium carbonate or sodium sulfate. The oxidizing agents can be represented by chlorinated sodium orthophosphate, chlorinated isocyanurate and perborate possibly with a copper catalyst or an organic activator. Additional disclosures relative to bleachcontaining detergent compositions for use in automatic dishwashers can be found in, for example, U.S. Pat. Nos. 3,410,804; 3,390,092; 3,248,330 and 3,595,968.
In addition, the presence of bleaching components in the detergent composition can have a detrimental effect on the activity of enzymes contained in the composition.
Various attempts have also been made to formulate bleach-free low-foaming detergent compositions for automatic dishwashing machines containing particular lowfoaming nonionics, builders and filler materials and additives adapted to provide a particular function. As an example, U.S. Pat. No. 3,022,250 to Grifo relates to low sudsing detergent compositions especially adapted for automatic dishwashing machines containing a phenol having therein an aliphatic substituent with an average of 9 carbons atoms per chain and a second substituent comprising condensed ethylene oxide in an average number of 4 molecules per molecule of phenol, together with builders consisting essentially of a mixture of sodium metasilicate and sodium tripolyphosphate in the proportion of 1 part of metasilicate to 3 parts of tripolyphosphate, the builders being present in the proportion of 95 parts of builder mixture to 5 parts of alkyl phenol ethylene oxide. The disclosures of U.S Pat. No. 3,048,548 to Martin et al. relate to substantially identical subject matter wherein the nonionic low-foaming surface-active agent can be represented by specific polyoxyalkylene glycol mixtures. U.S. Pat. No. 3,382,178 to Lissant et al. also pertains to automatic dishwashing compositions comprising a de-foaming nonionic surfactant having a specific formula and a small amount of an anti-oxidant for the purpose of reducing, inhibiting and/or preventing alkali degradation of the nonionic surfactant thereby rendering it stable in alkaline detergents, particularly during prolonged storage.
U.S. Pat. No. 3,576,122 to Payne et al relates to stable aqueous emulsions which are intended for use as laundering detergents and which contain nonionic surfactant and, as part of an emulsion stabilizer system, a hydrotropic material. Belgian Pat. No. 824,591 discloses an abrasive composition containing a silicaceous abrasive, an anionic detergent, especially alkyl benzene sulfonate, and a hydrotropic material such as sodium cumene sulfonate.
French Pat. No. 2,102,851 to Colgate-Palmolive, pertains to rinsing and washing compositions for use in automatic dishwashers. The compositions disclosed have a pH from about 6-7 and contain an amylolytic and, if desired, a proteolytic enzyme, which have been prepared in a special manner from animal pancreas and which exhibit a desirable activity at a pH in the range from about 6-7. German Patent Offenlegnngsschrift No. 2,038,103 relates to aqueous liquid or pasty cleaning compositions containing phosphate salts, enzymes and an enzyme-stabilizing compound. British Patent Specification No. 1,361,386 and U.S. Pat. No. 3,827,938 to Novo Therapeutisk Laboratories A/S, disclose proteolytic enzymes which exhibit high activity in alkaline systems, and exemplify their use in bleach-containing laundry detergent compositions.
Copending U.S. patent application Ser. No. 635,831; entitled: AUTOMATIC DISHWASHING DETERGENT COMPOSITION; Inventors: Edward J. Maguire, Jr., and Robert A. Staab; relates to bleach-free detergent compositions for use in automatic dishwashers comprising an alkoxylated nonionic surface-active agent and a sulfonated aromatic compatibilizing agent such as, for example, xylene-, toluene, cumene- and benzenesulfonate. U.S. patent application Ser. No. 4,79,969, now U.S. Pat. No. 4,001,132; entitled: AUTOMATIC DISHWASHING DETERGENT COMPOSITIONS; Inventor: Edward J. Maguire, Jr.; pertains to bleach-free detergent compositions for use in automatic dishwashers comprising an alkoxylated nonionic surface-active agent, a sulfonated aromatic compatibilizing agent such as, for example, xylene-, toluene-, cumene- and benzenesulfonate and a mixture of a water-soluble sulfate and a water-soluble sulfite. Concurrently filed U.S. patent application Ser. No. 699,416 entitled ENZYME CONTAINING AUTOMATIC DISHWASHING DETERGENT COMPOSITION, Maguire and Pancheri, relates to detergent compositions for use in automatic dishwashers, containing a nonionic surface active agent and a enzyme mixture containing a specifically selected proteolytic enzyme and an amylolytic enzyme.
While the prior art clearly recognizes the disadvantages of using aggressive bleaches in automatic dishwashing operations and also suggests bleach-free compositions by merely leaving out the bleach component, said art disclosures are silent about how to formulate bleach-free automatic dishwashing compositions capable of providing superior performance during conventional use.
It is an object of this invention to formulate bleach-free detergent compositions capable of providing superior anti-redeposition characteristics in automatic dishwashing operations.
It is an additional object of this invention to effectively incorporate enzymes in detergent compositions for use in automatic dishwashing operations with a view to optimize cleaning performance for a broad range of soils.
It is a further object of this invention to provide a detergent composition for use in automatic dishwashers capable of providing at least equal or better performance, with a lower level of active ingredients, than automatic dishwashing compositions commercially available now.
It is further an object of the invention to provide enzyme-containing compositions in a product form which reduces the tendency of the enzyme to become deactivated during the use of the product.
The above and other objects are now achieved by formulating bleach-free detergent compositions comprising a binary active system and specific enzymes.